This invention relates to an intake system for an internal combustion engine and more particularly to an intake system that improves the performance throughout the entire engine load and speed ranges.
In connection with engine induction systems, it has been a practice to employ a plenum chamber between an atmospheric air inlet and the chamber or chambers of the engine which are served. The use of plenum chambers tems to dampen pulsations in the intake charge flow and improves the charging efficiency of the engine. However, if a sufficient inlet opening is not provided into the plenum chamber, high power outputs may be restricted.
It has been proposed to provide a system wherein the plenum chamber is provided with a plurality of air intakes. However, where a plurality of air intakes are incorporated, the performance at mid-ranges may not be as good as desired. In order to improve mid-range performance, it has been proposed to incorporate some form of throttle valve arrangement for controlling the flow into the plenum chamber through the air intakes. However, the throttle valving arrangement should preferably be compact, simple and permit the desired tuning of the intake system.
It is, therefore, a principal object of this invention to provide an improved intake system for an internal combustion engine.
It is further object of this invention to provide an engine intake system including a plenum chamber with plural atmospheric air inlets and an improved throttle valve arrangement for controlling the flow through these inlets.
There have also been proposed intake systems for internal combustion engines that include compound or staged intake passages serving each combustion chamber of the engine. In this way, the individual intake passages may be tuned so as to perform improved performance under specific running conditions. These systems also can advantageously make the use of plenum chambers and copending application Ser. No. 634,795 and now U.S. Pat. No. 4,649,876, filed July 26, 1984, in the names Masatoshi Ohmi et al, entitled "Intake Means Of Internal Combustion Engine", and assigned to the assignee of this invention relates to one such system. A further improvement of this type of induction system including plural air inlets to the plenum air inlets to the plenum chamber is shown in copending application Ser. No. 002,730, filed Jan. 14, 1987, in the names of Iwao Masumoto et al, entitled "intake system For Multi Cylindered Engine", and assigned to the assignee of this invention.
It is a further object of this invention to provide an improved induction system of this type including a throttle valve arrangement for controlling the flow to the plenum chambers through the separate atmospheric air inlets.
It is a further object of this invention to provide an induction system of this type wherein a simple but effective throttle valve control is provided for the individual air inlets of the plenum chambers.